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1.
In this talk, the interaction of a single photon injected to a single atom is studied, for which initially the photon is uncorrelated with the atom. The spontaneous emitted photon will then evolve to be entangled with the atom on their continuous kinetic variables (momentum) in the process of resonant scattering. We find the relations between the entanglement and their physical control parameters (such as the linewidth of the injected photon wave packet, and that of the atomic wave packet, etc. ), which indicates that high entanglement can be reached by broadening the scale of the atomic wave or squeezing the linewidth of the incident single-photon pulse. 相似文献
2.
Implementation of quantum search scheme by adiabatic passage in a cavity--laser--atom system
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This paper proposes a scheme for implementing the adiabatic quantum
search algorithm of different marked items in an unsorted list of
N items with atoms in a cavity driven by lasers. N identical
three-level atoms are trapped in a single-mode cavity. Each atom is
driven by a set of three pulsed laser fields. In each atom, the same
level represents a database entry. Two of the atoms are marked
differently. The marked atom has an energy gap between its two
ground states. The two different marked states can be sought out
respectively starting from an initial entangled state by controlling
the ratio of three pulse amplitudes. Moreover, the mechanism, based
on adiabatic passage, constitutes a decoherence-free method in the
sense that spontaneous emission and cavity damping are avoided since
the dynamics follows the dark state. Furthermore, this paper extends
the algorithm with m (m>2) atoms marked in an ideal situation.
Any different marked state can be sought out. 相似文献
3.
We propose a scheme for generating entangled squeezed vacuum states of electromagnetical fields. The scheme is based on cavity QED. In this scheme, an atom interacts, successively, with a classical field, two quantum cavity fields, and another classical field. By detecting the final states of the atom, the two quantum cavity fields will be projected to an entangled state. 相似文献
4.
Superposition of Fock states via adiabatic passage in a coupled four-level atom-cavity system
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We have investigated the behaviour of an atom-cavity system via a stimulated Raman adiabatic passage technique in a four-level system, in which two dark states are present. We find, because of the coherent control field, that a superposition of Fock states can be prepared, even when the cavity is initially not in its vacuum state. This method provides a way to generate arbitrary quantum states of a cavity field. 相似文献
5.
ZHENG Shi-Biao 《理论物理通讯》2006,46(4):613-616
We propose a scheme to teleport a superposition of three states of an atom trapped in a cavity to a second atom trapped in a remote cavity. The scheme is based on the detection of photons leaking from the cavities after the atom-cavity interaction. 相似文献
6.
ZHENG Shi-Biao 《理论物理通讯》2006,46(10)
We propose a scheme to teleport a superposition of three states of an atom trapped in a cavity to a second atom trapped in a remote cavity. The scheme is based on the detection of photons leaking from the cavities after the atom-cavity interaction. 相似文献
7.
Z. J. Deng L.-M. Liang W. L. Yang 《International Journal of Theoretical Physics》2010,49(8):1904-1910
We propose a simple scheme to implement multi-qubit quantum Grover search with atomic ensembles by adiabatic passage. The
scheme is immune to the atomic spontaneous emission, cavity decay and fiber decay. Furthermore, the process can be speeded
up with atomic ensemble instead of single atom, which is important in view of decoherence. With each atomic ensemble confined
in an individual cavity, our scheme is experimentally scalable to multi-qubit cases. 相似文献
8.
We propose a scheme to implement a two-qubit conditional quantum phase gate via a single mode cavity and a cascade four-level atom assisted by a classical laser. The quantum information is encoded on the Fock states of the cavity mode and the two metastable ground states of the atom. Even under the condition of systematic dissipations,this scheme can also be realized with fidelity of 98.6% and success probability of 0.767. 相似文献
9.
N. Sangouard X. Lacour S. Guérin H. R. Jauslin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(3):451-456
We propose a scheme for the construction of a CNOT gate by
adiabatic passage in an optical cavity. In opposition to a previously proposed method, the technique is not based on fractional
adiabatic passage, which requires the control of the ratio of two pulse amplitudes. Moreover, the technique constitutes a
decoherence-free method in the sense that spontaneous emission and cavity damping are avoided since the dynamics follows dark
states. 相似文献
10.
We propose a scheme to generate atomic cluster states of arbitrary
configuration in the cavity quantum electrodynamics (QED) system. The
process is achieved via adiabatic evolution of dark states, which only
requires adiabatically increasing or decreasing Rabi frequencies of laser.
Thus it allows the robust implementation of entanglement against certain types of errors. Our scheme is relatively decoherence-free in the sense that excited atomic states are never populated and excited cavity photon states can be made negligible in certain conditions. 相似文献
11.
CAI Jian-Wu FANG Mao-Fa LIAO Xiang-Ping ZHENG Xiao-Juan 《理论物理通讯》2006,46(6):983-986
We propose a scheme to implement a two-qubit conditional quantum phase gate via a single mode cavity and a cascade four-level atom assisted by a classical laser. The quantum information is encoded.on the Flock states of the cavity mode and the two metastable ground states of the atom. Even under the condition of systematic dissipations, this scheme can also be realized with fidelity of 98.6% and success probability of 0.767. 相似文献
12.
We present a scheme to prepare an optical “quantum switch”, a superposition of “open” and “closed” states. The scheme is based on the interaction of an Λ-type three-level atom with a single-mode of quantized cavity field and an external classical driving field, in the regime where the atom and fields are highly detuned. We show how this interaction can be used to generate coherent states of the cavity field in contrast to the usual method used in microwave cavity QED of injecting a coherent state into a cavity. A combination of switches could be used to prepare a quantum superposition of coherent field states located simultaneously in two cavities. Compared with previous proposals, our scheme is simplified due to economizes the Ramsey zone and the time required for the state generation is short. 相似文献
13.
We report on the first observation of stimulated Raman scattering from a Lambda-type three-level atom, where the stimulation is realized by the vacuum field of a high-finesse optical cavity. The scheme produces one intracavity photon by means of an adiabatic passage technique based on a counterintuitive interaction sequence between pump laser and cavity field. This photon leaves the cavity through the less-reflecting mirror. The emission rate shows a characteristic dependence on the cavity and pump detuning, and the observed spectra have a subnatural linewidth. The results are in excellent agreement with numerical simulations. 相似文献
14.
Possible Realization of Cluster States and Quantum Information Transfer in Cavity QED via Raman Transition
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We present a scheme to generate cluster states with many scheme, no transfer of quantum information between the atoms in cavity QED via Raman transition. In this atoms and cavities is required, the cavity fields are only virtually excited and thus the cavity decay is suppressed during the generation of cluster states. The atoms are always populated in the two ground states. Therefore, the scheme is insensitive to the atomic spontaneous emission and cavity decay. We also show how to transfer quantum information from one atom to another. 相似文献
15.
Scheme for Quantum Entanglement Swapping on Cavity QED System 总被引:1,自引:0,他引:1
We propose a scheme for realizing quantum entanglement swapping
between the atoms in cavity QED. With only virtual excitation of the cavity during the interaction between the atoms and cavity, the scheme is insensitive to the cavity mode states and the cavity decay. The ideas can also be utilized for realizing entanglement swapping between the atomic levels in a single atom and the atomic levels in the Bell states and
between the atomic levels in the Bell states and the atomic
levels in the W states. 相似文献
16.
In this paper, we present a scheme for generating cluster-type entangled coherent states via cavity QED. The scheme is based
on the off-resonant interaction between one atom and N cavities, so the spontaneous emission of the atom can be ignored. The initial states of the N cavities are all prepared in vacuum states. We also discuss the experimental feasibility. 相似文献
17.
We propose a scheme to implement the Deutsch-Jozsa algorithm by using Schroedinger cat states in cavity quantum electron-dynamics (QED). The scheme is based on the Raman interaction of a degenerate three-level A-type atom with a coherent state in a cavity. By using Schroedinger cat states, the atomic spontaneous emission can be minimized and the Hadamard transformation in our scheme is not needed. 相似文献
18.
SONG Ming-Yu 《理论物理通讯》2011,56(5):837-844
We proposed an efficient scheme for constructing a quantum controlled phase-shift gate and generating the cluster states with rf superconducting quantum interference devices (SQUIDs) coupled to a microwave cavity through adiabatic evolution of dark eigenstates. During the operation, the spontaneous emission is suppressed since the rf SQUIDs are always in the three lowest flux states. Considering the influence from the cavity decay with achievable
experimental parameters, we numerically analyze the success probability and the fidelity for generating the two-SQUID maximally entangled state and the controlled phase-shift gate by adiabatic passage. 相似文献
19.
A scheme is proposed for generating entangled W states with four
cavity modes. In this scheme, we send a V-type three-level atom
through two identical two-mode cavities in succession. After the
atom exits from the second cavity, the four cavity modes are
prepared in the W state. On the other hand we can obtain
three-atom W states by sending three V-type three-level atoms
through a two-mode cavity in turn. The present scheme does not
require conditional measurement, and it is easily generalized to
preparing $2n$-mode W states and $n$-atom W states. 相似文献
20.
We propose a novel scheme for the efficient production of entangled states for N photons of the form |N>(a)|0>(b) + |0>(a)|N>(b) (NOON states) based on the resonant interaction of a pair of quantized cavity modes with an ensemble of atoms. We show that, in the strong-coupling regime, the adiabatic evolution of the system tends to a limiting state that describes mesoscopic entanglement between photons and atoms which can easily be converted to a purely photonic or atomic NOON state. We also demonstrate the remarkable property that the efficiency of this scheme increases exponentially with the cavity cooperativity factor, which gives efficient access to high number NOON states. The experimental feasibility of the scheme is discussed, and its efficiency is demonstrated numerically. 相似文献